diff --git a/addons/web/static/src/js/framework/pyeval.js b/addons/web/static/src/js/framework/pyeval.js
index bcab0b0717f..c1b823ed48f 100644
--- a/addons/web/static/src/js/framework/pyeval.js
+++ b/addons/web/static/src/js/framework/pyeval.js
@@ -436,6 +436,22 @@ datetime.datetime = py.type('datetime', null, {
             this.second,
             this.microsecond / 1000);
     },
+    __add__: function (other) {
+        if (!py.PY_isInstance(other, datetime.timedelta)) {
+            return py.NotImplemented;
+        }
+        var s = tmxxx(this.year, this.month, this.day + other.days, this.hour, this.minute, this.second + other.seconds);
+        return datetime.datetime.fromJSON(s.year, s.month, s.day, s.hour, s.minute, s.second);
+    },
+    __sub__: function (other) {
+        if (py.PY_isInstance(other, datetime.timedelta)) {
+            return py.PY_add(this, py.PY_negative(other));
+        }
+        return py.NotImplemented;
+    },
+    fromJSON: function (year, month, day, hour, minute, second) {
+        return py.PY_call(datetime.datetime, [year, month, day, hour, minute, second]);
+    },
 });
 
 datetime.date = py.type('date', null, {
diff --git a/addons/web/static/test/evals.js b/addons/web/static/test/evals.js
index b6a3b4177e8..bb5b5564ba4 100644
--- a/addons/web/static/test/evals.js
+++ b/addons/web/static/test/evals.js
@@ -302,6 +302,25 @@ odoo.define_section('eval.types', ['web.pyeval'], function (test, mock) {
             '2015-02-02');
     });
 
+    test('timedelta', function (assert, pyeval) {
+        assert.strictEqual(
+            py.eval("(datetime.datetime(2017, 2, 15, 1, 7, 31) + datetime.timedelta(days=1)).strftime('%Y-%m-%d %H:%M:%S')",
+                    pyeval.context()),
+            "2017-02-16 01:07:31");
+        strictEqual(
+            py.eval("(datetime.datetime(2012, 2, 15, 1, 7, 31) - datetime.timedelta(hours=1)).strftime('%Y-%m-%d %H:%M:%S')",
+                    pyeval.context()),
+            "2012-02-15 00:07:31");
+        strictEqual(
+            py.eval("(datetime.datetime(2012, 2, 15, 1, 7, 31) + datetime.timedelta(hours=-1)).strftime('%Y-%m-%d %H:%M:%S')",
+                    pyeval.context()),
+            "2012-02-15 00:07:31");
+        strictEqual(
+            py.eval("(datetime.datetime(2012, 2, 15, 1, 7, 31) + datetime.timedelta(minutes=100)).strftime('%Y-%m-%d %H:%M:%S')",
+                    pyeval.context()),
+            "2012-02-15 02:47:31");
+    });
+
     test('datetime.tojson', function (assert, pyeval) {
         var result = py.eval(
             'datetime.datetime(2012, 2, 15, 1, 7, 31)',